Exploring biophysical components in rain-fed potato systems in the Peruvian Central Andes

D. Grados, R. Heuts, S. García, E. Schrevens
Rain-fed potato systems play a key role in food security being the most important cash crop in the Peruvian mixed farming systems. Sustainable use of biophysical resources has not been fully quantified for these agroecosystems. The main objective is the assessment of biophysical resource management in rain-fed potato systems in the Peruvian Central Andes (Mantaro Valley). Indicators of nutrient use efficiencies and labor productivity were calculated. In addition, two experiments were established in the 2014-2015 growing season to evaluate inorganic fertilization practices (nitrogen) and seed quality. From 2005 until 2015, 55 potato pilot plots located on a transect of the Valley, were investigated at field level. Full climate data were recorded at different altitudes. During the study period, a mean temperature altitudinal gradient was noticed from 8.9 until 11.4°C. The range of total annual rainfall was laying between 558 and 1050 mm. The amounts of inorganic fertilization doses were 26-317 kg ha‑1, 32-144 kg ha‑1 and 26-146 kg ha‑1 for N, P and K on average, respectively. C inputs rates ranged from 42 to 3,803 kg ha‑1. The amount of seed fluctuated from 1,405 to 1,987 kg ha‑1. A large variability of mean fresh tuber yield was found (15-28 t ha‑1). Nutrient use efficiencies varied between 12.3 and 26.5, 23.3-153.8 and 14.7-99.9 kg DW yield kg‑1 nutrient for N, P and K. Values of land to labor ratio (0.07-0.50 m2 MJ‑1) indicated high heterogeneity of labor allocation. Soil chemical fertility is not representing a major constraint if it is enhanced with rational use of inorganic nitrogen, however, moderate acid soils were found. A self-subsistence (organic oriented) and a market (inorganic and mixed oriented) agriculture system were defined with principal component analysis biplots (based on standardized biophysical inputs and total yield). Field experiments proved that seed quality is not a critical factor, and 39-74 t ha‑1 potential yield is achievable with 200 to 300 kg N ha‑1. Further developments in systems' simulation are required to optimize the overall technical sustainability of potato production in the study regions.
Grados, D., Heuts, R., García, S. and Schrevens, E. (2021). Exploring biophysical components in rain-fed potato systems in the Peruvian Central Andes. Acta Hortic. 1326, 247-254
DOI: 10.17660/ActaHortic.2021.1326.33
farming systems, smallholder agriculture, resource use efficiency, principal component analysis biplots

Acta Horticulturae